What happen when a solution of potassium chromate is treated with an excess of dil. Nitic acid?
A. `Cr^(3+)` and `Cr_2O_7^(2-)` are formed
B. `Cr_2O_7^(2-)` and `H_2O` are formed
C. `CrO_4^(2-)` is reduced to +3 state of Cr
D. `CrO_4^(2-)` is oxidized to +7 state of Cr